S: Rat Trap Car
BC: Thank you for reading our book. Hope you enjoyed it! =] By: Megan M., Jackie I., and Brickell D.
FC: Rat Trap Car By: Brickell, Jackie, and Megan
1: We chose this design for our rat trap car because we thought it'd be successful. It has 4 wheels for better balance. When the rat trap pulls the string, the axel will move, and keep moving because of Newton's 1st law of motion.
2: Build Day 1 We have decided on our web media and picked a design for the rat trap car.
3: Build Day 2 We drew the diagram and created the reasoning. We have also shared our web media(mixbook) with our teacher, Mrs. Hockman. Build Day 3 We decided to use one big wheel in the back instead of two to give the car more power. Also, with one big wheel, we don't need an axel or a notch, making the building process easier. We have started working on our design and our first test run should be on the 27th.
4: Build Day 4 Today we worked on finishing our project. We attatched the back wheel and changed the axel to the front wheels. With the back wheel, we attatched it to the car with a wood ruler. At first we used duct tape to hold it, but we were afraid it would fall, so we used wood glue instead. But the wood glue didn't hold either, so we are going to figure it out over the weekend. Also, we have decided that we have to drill a bigger hole for the front axel to fit through. We have attatched a wooden dowel to the lever on the rat trap to give it farther distance and speed. With the wooden dowel, we had to cut off 4 inches in order to meet the length requirement. During the weekend we are going to get together as a group to finish the project.
5: This is our rat trap car in the making
6: Build Weekend We have attatched the wheels, front and back. To put the back wheel on, we used zip ties and to attatch the bottom ruler we used a staple gun (adult supervision, of course). Also, we took off one tension from the rat trap, because the string kept breaking from the tension.
7: Test Day 1 We had to get rid of one tension because with both the string broke. With both tension, the car went 0 inches. With one tension, the rat trap car went forward 9 inches. We tested it again and it went 6in. still unravling more string. Now we are going to try to put masking tape around the back wheel to keep the string from unraveling. We think this will work because it will make traction. Our car went pretty straight during our trial and did not curve much. It took less than a second for our car to reach 9 inches.
8: Test 2 It went 16 in. with the masking tape. We are going to see if there is a difference in duct tape. We also put a peice of duct tape to hold the extra fishing line in place. This will help it to not unravel. With the duct tape around the wheel it went 23 in. With the duct tape around the wheel it went farther but not enough to win. :( The tape holding the string down stopped the car from moving farther.
9: Test 3 We have motified our project by using 3 wheels; 1 in front 2 in back. The axel for the back wheel is where we wrapped the string. Also on the back wheels we added double sided tape to give it traction. When it was tested it went 3m. and 6in.!!!!!!!!! We are getting close to our goal!
10: This is our modified project!
11: We have made another modification to our rat trap car. We have added a wooden dowel to the lever of the rat trap to see if it will go farther. With the 9 in. wooden dowel attatched, the string will be able to pull the axel longer causing the car to go farther, and possibly faster. It goes a little more the 2m.
13: This velocity graph shows the velocity over time. For example, the velocity is like how fast a car goes. So a car can go 60 mph and it'd take the car around, hmm let's just say 7 seconds, to travel 2 miles at the speed, or velocity, of 60 mph. Our graph shows how fast our car went each second. As time went on, our car simply got slower. We think that our car went slower because when the handle finishes clamping down, there is no longer force applied, so the car is only relying on what speed it had before. So, the friction force slowed it down.
14: This is our acceleration graph, which shows our cars average velocity.
15: Our acceleration graph is how long it takes for the car to reach a certain velocity. Like how fast a car can get from 0 to 60mph.
16: MODIFICATION! We have chosen to use a metal dowel instead of a wooden dowel. The metal one will be sturdier and more durable, which will help in the race. In one of our testings, the rat trap car went about 3 meters with the metal dowel. Our car goes generally straight most of the time. Our average velocity is 1.5 meters per second. Our average acceleration is the velocity divided by the average time, which was .5 meters per seconds squared.
18: This is the modified version of our car with the metal rod. This will be our final modification for our car.
19: Newton's 1st Law- A body in motion will stay in motion unless an outside force acts upon it, and a body at rest will stay at rest unless an outside force acts upon it. The rat trap car will keep moving until the friction of the carpet stops it. It stays at rest until you release the handle, which makes it go forward. Newton's 2nd Law-The greater the mass the more force it will take to accelerate that mass. F=ma When we added more duct tape to the car, it added weight, and it didn't go as far or as fast as when we tried it without the duct tape. Newton's 3rd Law- Every action has an equal but opposite reaction. Pulling the rat rap backwards and releasing the handle makes the car go forward, which is the opposite reaction.